Study of human breast cancer tissues is necessary to validate hypotheses derived from laboratory studies of cell lines and animal models. However, both breast cancer diagnosis and surgery have changed dramatically over the past 10 years, making it more difficult to obtain breast cancer tissues or research studies. We have therefore devised new strategies for tissue acquisition that will increase our accrual, particularly of smaller cancers, without compromising accurate pathologic diagnosis of the patient specimens. The specific aims of this proposal are: 1) To continue to obtain breast cancer and co-existing normal breast tissue from patients undergoing cytoreductive surgery for breast cancer; 2) To obtain frozen core biopsy specimens from patients undergoing radiologically guided core biopsies for diagnosis for breast cancer; 3) To provide a detailed pathologic report on each tissue specimen collected by the Tissue Bank; 4) To provide pathology support services for SPORE projects utilizing tissue and xenografts. 5) To work with the Administrative Core to address requests made to the SPORE for human breast tissue specimens. With these Aims, we will meet the needs of the projects of this SPORE for tissue and pathologic expertise and will maximize the usefulness of our tissue resources for projects within and outside the Duke SPORE.